Laminate structure with polycarbonate sheets and method of making

ABSTRACT

Disclosed is a decorative laminate structure having at least two sheets of polycarbonate and at least one decorative image layer there-between two sheets of polycarbonate, and a method of making the decorative laminate structure. Through heat and pressure the sheet layers and the decorative image layer are bonded together resulting in a decorative laminate structure of this invention. This product is intended for use primarily to produce decorative articles which include counter tops, table tops, cabinet doors, game boards, toys, panels for shower stalls, hot tubs, markerboards, indoor and outdoor signs, seamless vanity tops including sink, soap dish, back splash, flooring and others.

RELATED APPLICATIONS

This application is a Divisional of U.S. patent application Ser. No.10/465,465 ('465), filed on Jun. 18, 2003, entitled “Laminate Structurewith Polycarbonate Sheets and Method of Making”, which claims priorityto U.S. Provisional application Ser. No. 60/389,392, filed Jun. 18,2002, and is further a continuation-in-part of U.S patent applicationSer. No. 10/086,269 ('269 application), filed on Mar. 1, 2002, entitled“Laminated Article and Method of Making Same”, which claims priority toU.S. Provisional Patent Application Ser. No. 60/273,076, filed on Mar.5, 2001, entitled “Lamination of Dissimilar Materials and Method forMaking Same”. Each of the aforementioned patent applications isincorporated herein by reference in its respective entirety.

FIELD OF THE INVENTION

The present invention relates to a decorative laminated structure havingdecorative images and/or custom colors embedded therein and a method ofmaking the decorative laminated structure. The decorative laminatestructures according to the present invention may be used not only inthe construction industry as wall coverings, as glazing for windows, inpartitions, as decorative paneling and in select furniture applications,but also in high-heat and performance driven applications, such asautomotive, marine, lighting, flooring, and aerospace. One or bothsurfaces of the articles may be textured during the formation of thearticles.

BACKGROUND OF THE INVENTION

There has been a great demand for translucent building materials withdecorative images, textures and colors. Traditionally these materialshave been made by mixing colors in the base resin material limiting theoptions to only large runs thus eliminating the possibility ofcustomizing colors for each project.

Laminate structures are composites made from any one of several types ofthermosetting plastic materials and may contain a printed pattern or animage. However, to date, the production of such laminated structures hasoften required complex processing techniques, added production time,and/or additional capital. In addition, these laminate structures couldnot be easily thermoformed and were typically rigid and brittle. Also,certain laminate materials which offer the prospect of providingimproved properties in decorative laminate structures often do notreadily adhere to adjacent layers, which then resulted in non-uniformlamination or delamination after a period of use.

U.S. Pat. Nos. 5,894,048, 5,643,666, 5,998,028, 5,958,539, 6,025,069 andPCT Application No. WO 97/22474 disclose a decorate laminate structurewhich uses polyethylene teraphtalate glycol polyester (PETG polyester).

BRIEF SUMMARY OF THE INVENTION

In a first aspect, the invention provides a method of making adecorative laminate structure including providing a first sheetcomprising polycarbonate, the first sheet having a thickness between0.13 and 12.7 mm, providing a second sheet comprising polycarbonate, thesecond sheet having a thickness between 0.13 and 12.7 mm, and providingat least one a decorative image layer between the first and secondsheet. The first and second sheet with the decorative image layerthere-between are heated and pressed at a maximum temperature between193 and 249° C. and a maximum pressure between 138 and 2069 kPa. Thetime at maximum temperature and pressure is between 0.1 and 20 minutes.

In another aspect, the invention provides a decorative laminatestructure including a first sheet comprising polycarbonate, the firstsheet having a thickness between 0.13 and 12.7 mm, a second sheetcomprising polycarbonate, the second sheet having a thickness between0.13 and 12.7 mm, and at least one a decorative image layer between thefirst and second sheet.

In yet another aspect, the invention provides a decorative laminatestructure including a first sheet comprising polycarbonate, the firstsheet having a thickness between 0.13 and 12.7 mm; a second sheetcomprising polycarbonate, the second sheet having a thickness between0.13 and 12.7 mm; a third sheet of polycarbonate, the third sheet havinga thickness between 0.13 and 12.7 mm; at least one first decorativeimage layer between the first and second sheet; and at least one seconddecorative image layer between the second and third sheet.

These and other aspects are discussed in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is better understood with reference to theaccompanying drawings and detailed description wherein:

FIG. 1 is a partially separated, cross-section of substantially planardecorative laminate structure according to the present invention.

FIG. 2 is a partially separated, cross-section of a substantially planardecorative laminate structure according to the present invention.

FIG. 3 is an illustration of decorative laminate structures.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is provided as an aid to thosedesiring to practice the present invention. The following description isnot to be construed as limiting the instant invention, since those ofordinary skill in the art will realize that various modifications,changes and substitutions made can be made in various materials andmethods disclosed herein, without departing from the spirit or the scopeof the present inventive discovery. Instead, the present invention isdefined by the claims appended hereto and the equivalents encompassedthereby.

The invention relates to a decorative laminate structure and a method ofmaking the decorative laminate structure. The laminate structure hasaesthetically desirable surface appearance, for example that of wood,stone, kiln cast glass, and solid surface saturated colored products.

The decorative laminate structures include:

-   -   (1) a first sheet comprising polycarbonate, the first sheet        having a thickness between 0.13 and 12.7 mm;    -   (2) a second sheet comprising polycarbonate, the second sheet        having a thickness between 0.13 and 12.7 mm; and    -   (3) at least one a decorative image layer between the first and        second sheet.

The decorative laminate structures also include:

-   -   (1) a first sheet comprising polycarbonate, the first sheet        having a thickness between 0.13 and 12.7 mm;    -   (2) a second sheet comprising polycarbonate, the second sheet        having a thickness between 0.13 and 12.7 mm;    -   (3) a third sheet of polycarbonate, the third sheet having a        thickness between 0.13 and 12.7 mm;    -   (4) at least one first decorative image layer between the first        and second sheet; and    -   (5) at least one second decorative image layer between the        second and third sheet.

The methods of making a decorative laminate structure include:

-   -   (1) providing a first sheet comprising polycarbonate, the first        sheet having a thickness between 0.13 and 12.7 mm;    -   (2) providing a second sheet comprising polycarbonate, the        second sheet having a thickness between 0.13 and 12.7 mm;    -   (3) providing at least one a decorative image layer between the        first and second sheet; and    -   (4) heating and pressing the first and second sheet with the        decorative image layer there-between at a maximum temperature        between 193 and 249.degree. C. and a maximum pressure between        138 and 2069 kPa, wherein the time at maximum temperature and        pressure is between 0.1 and 20 minutes.

The method may further comprise a step in which the first and secondsheet with the decorative image layer there-between are cooled atpressure between about 7 and 2065 kPa.

According to FIG. 1, the decorative laminate structure 1 comprises afirst polycarbonate sheet 2, a decorative image layer 3, and a secondpolycarbonate sheet 4.

According to FIG. 2 the decorative laminate structure 5 according to thepresent invention comprises a first polycarbonate sheet 6, a decorativeimage layer 7, and a second polycarbonate sheet 8. The decorativelaminate structure further includes a protective layer 9 including ahard coat 10.

The traditional laminate structures and method of making the laminatestructures often require laminating enhancers such as adhesives orcoupling agents. A great advantage of this invention is that the methodof making the decorative laminate structure as described herein does notrequire use of the laminating enhancers. Preferably, heat and pressureapplied to the laminated structure are sufficient to bond the firstsheet, the second sheet and the decorative image layer.

Furthermore, one possible explanation for the success of the decorativelaminate structure of this invention is based on the polycarbonateproperties. For example, properties such as high-melting temperature,increased rigidity, strength, and high impact resistance of thepolycarbonate allow the decorative laminate structure of this inventionto be used in high-heat and performance driven applications such asautomotive, marine, lighting, flooring, commercial construction,signage, exterior use and aerospace.

As used herein, “first,” “second,” and “third” in connection with thepolycarbonate sheets are arbitrary and do not refer to positions andorder of the sheet layers relative to each other and the decorativeimage layer. Furthermore, the first and second sheets are notnecessarily the outermost sheets of the decorative laminate structureaccording to the invention. Therefore, the decorative laminate structuremay contain multiple sheets layers on each side of the decorative imagelayer as well as multiple decorative image layers.

The sheet material used in the preparation of the decorative laminatestructures of our invention may be transparent, translucent, or onesheet may be opaque, depending on the particular aesthetic effectdesired. The first and second sheets may differ in degree oftransparency or translucency and also in color.

The thickness of the sheet layers used in the preparation of thedecorative laminate structure depends upon a number of factors such asfunctionality, weight, cost, etc. The first sheet has a thickness in therange of about 0.13 to 12.7 mm (0.005-0.5 inch), preferably about 0.74to 10 mm (0.03-0.4 inch), more preferably in the range of about 1.48 to6.35 mm (0.063-0.126 inch), and most preferably in the range of 2.22 to6.35 mm. The second sheet typically has a thickness in the range ofabout 0.13 to 12.7 mm (0.005-0.5 inch), preferably about 0.74 to 10 mm(0.03-0.5 inch), more preferably in the range of about 1.48 to 6.35 mm(0.063-0.126 inch), and most preferably in the, range of 2.22 to 6.35mm. The thickness of the sheets is limited only by functionality. Forexample, the thickness of the sheet layers is greater in decorativelaminates structures used in horizontal applications, such as worksurfaces, flooring, and ceilings.

The first and the second sheets of the decorative laminated structureaccording to the present invention comprise polycarbonate. The term“polycarbonate” refers to polycarbonates for use in the production ofthe decorative laminated structures of the invention. Polycarbonates arethermoplastic, aromatic polymers and include homopolycarbonates,copolycarbonates and copolyestercarbonates and mixtures thereof whichhave average molecular weights of about 8,000 to more than 200,000,preferably of about 20,000 to 80,000 and an intrinsic viscosity (I.V.)of 0.40 to 1.5 dl/g as measured in methylene chloride at 25.degree. C.Preferably, the glass transition temperature of polycarbonates rangesfrom 145 to 148.degree. C. The material's “glass transition temperature(Tg)” is defined as the temperature below which molecules have verylittle mobility. On a larger scale, polymers are rigid and brittle belowtheir glass transition temperature and elastic above it. Tg is usuallyapplicable to amorphous phases and is commonly applicable to glasses andplastics.

Polycarbonates are a well known class of high impact resistantthermoplastic resins characterized by optical clarity and highductility. Polycarbonates can be defined as polymers containingrecurring carbonate groups (—O—CO—O—) in the main chain. Aromaticpolycarbonates are of particular interest in the practice of thisinvention. These polymers are known per se and are generally prepared byreacting a dihydric phenol, or bisphenol, with a carbonate precursor,e.g., phosgene, a halogen formate, or a carbonate ester (see GermanOffenlegungsschriften 2,063,050; 1,561,518; 1,570,703; 2,211,956;2,211,957 and 2,248,817; French Patent 1,561,518; and the monograph byH. Schnell, “Chemistry and Physics of Polycarbonates”, IntersciencePublishers, New York, N.Y., 1964, all of which are incorporated hereinby reference).

For the polycarbonate, commercially available products may be used and,among them, polycarbonates obtained by the use of the bisphenol A arepreferred for their good mechanical properties and also excellenttransparency. For example, polycarbonate MAKROLON.RTM.3105 from BayerPlastics is a preferred polycarbonate to use in this invention. Othertransparent polycarbonate materials include, for example LEXAN.RTM.polycarbonate which can be purchased from General Electric. Also,copolymers of polycarbonates with polyesters may be used.

The decorative image layer preferably includes fabric, metallic wire,rod and/or bar, papers or photographic images, crushed glass, andvegetation, such as wood chips, grasses, flowers, wheat, and thatch. Thedecorative image layer may display images or decorative designs or maybe of a solid color. The melting point of the decorative image layershould be sufficiently high to avoid any degradation or distortion ofthe decorative image layer during the manufacture or processing of thedecorative laminate structure of this invention. Preferably, thedecorative image layers embedded within the decorative laminatestructure of the present invention are substantially continuous andconstitute a distinct image layer or laminate, as in FIG. 3B.Alternatively, the decorative image layers embedded within thedecorative laminate structure can be made of discontinuous segments, forexample as illustrated in FIGS. 3A, C and D.

The decorative image layer preferably ranges from about 0.0254 mm (0.001inch) to about 1.524 mm (0.06 inch) in thickness, and more preferably0.0254 mm (0.001 inch) to 0.05 mm (0.002 inch), and most preferablyabout 0.04 mm (0.0015 inch) in thickness. However, polymeric filmsthinner or thicker may be used in the decorative image layer dependingon the equipment available, and under such conditions the thickness islimited only by functionality.

In a preferred embodiment of the present invention, the decorativelaminate structure includes at least one first decorative image layerembedded between the first and the second polycarbonate sheet and atleast one second decorative image layer embedded between the second andthe third polycarbonate sheet. Furthermore, the first and third sheetsare not necessarily the outermost sheets of the decorative laminatestructure according to the invention. Therefore, the decorative laminatestructure may contain multiple sheet layers on each side of thedecorative image layer as well as multiple decorative image layers.

In one embodiment of the present invention, the decorative image layercomprises a fabric comprised of textile fibers. The fabric may displayimages or decorative designs which have been produced, e.g., by weavingor knitting techniques, in the fabric. The fabrics, which may be used inproducing the decorative laminate structures of the present invention,comprise textile fibers, i.e., fibers of natural-occurring,semi-synthetic or synthetic polymeric materials. For example, thefabrics may be prepared from cotton, wool, silk, rayon (regeneratedcellulose), polyester such as polyethylene terephthalate, syntheticpolyamides such as nylon 66 and nylon 6, acrylic, modacrylic, andcellulose acetate fibers. The melting point of the textile fibers shouldbe sufficiently high to avoid any degradation or distortion of thefabric during the manufacture or processing of the decorative laminatestructures of this invention.

The fabric may be woven, spun-bonded, knitted, or prepared by otherprocesses well known in the textile trade and may be uncolored, e.g.,white, or colored by conventional dyeing and printing techniques.Alternatively, the fabrics may be produced from dyed yarn or fromfilaments and yarn derived from mass colored polymers. Preferably, thefabrics present within the decorative laminate structure aresubstantially continuous and constitute a distinct image layer orlaminate.

In one embodiment of this invention, the decorative laminate structurecomprising a decorative image layer comprising a fabric can be used inthe manufacture of decorative walls, partitions, and glazingapplications.

In another embodiment, the decorative image layer comprises metallicwire, rod, or bar. The metal wire may be formed by a variety oftechniques to produce metal mesh fabric, screens, or open mesh havinghigh transparency. The metal wire, rod or bar may be woven, welded,knitted, or fabricated by means of other processes well known in themetal wire fabrication trade. The metallic wire, rod and bar may be ofvarious colors such as black, gray, green, blue, etc. The metallicelement of the decorative image layer can be composed of differentmetallic materials such copper, aluminum, stainless steel, steel,galvanized steel, titanium, etc. or combinations thereof. The metalliccomponent of the decorative image layer may be prepared from wirefilaments, rods and bars having various cross-sectional areas andgeometries, e.g., generally circular, oval or relatively flat. Thethickness or diameter of the wire, rod and bar may range from about0.001 to 19 mm (0.00004 to 0.75 inch) depending upon the desired use ofthe thermoplastic structure. Preferably, the thickness or diameter ofthe wire, rod, or bar will be in the range of about 0.0254 to 5.08 mm(0.001 to 0.20 inch).

In one embodiment of this invention, the decorative laminate structurecomprising a decorative image layer including wire, rod, or bar can beused in the manufacture of decorative walls, partitions, and securityglazing applications.

In further embodiment, the decorative image layer comprises a printed orcolored image. Preferably, the printed or colored decorative image layerhas opposed surfaces wherein an image is printed on one of the surfacesand/or the decorative image layer contains coloration. More than oneprinted or colored decorative image layer may be used in the decorativelaminate structure of the present invention. The use of multipledecorative image layers can provide a 3-dimensional or “floating”appearance to the decorative images or lettering in the printed orcolored decorative image layers. Each of the printed or coloreddecorative image layers is joined to a first sheet on one of itssurfaces such that the image or coloration can be seen through the firstsheet without significant distortion. The printed or colored decorativeimage layer may comprise any suitable polymeric material which iscompatible with the materials used for the first sheet and the secondsheet, inks, and other materials used in fabricating the decorativelaminate structure. Preferably, the decorative image layer comprises apolyvinyl chloride (PVC) or copolyester.

In another embodiment, the image or coloration is printed on the bottomside of the decorative image layer in which case the polymer used toprepare the decorative image layer should be transparent. Any image maybe used provided it has an aesthetically desirable surface appearancesuch as an image of a natural building material. As used herein the term“building material” means a material of suitable strength, durability,impact resistance, and rigidity such that it can be used in constructionof articles that could also be constructed of natural building materialssuch as, but not limited to, wood or stone.

The image to be printed on the decorative image layer can be preparedaccording to conventional photographic printing processes or with adigitized database generated from a photographic image-. Digitizing andstoring the image may be accomplished through any of a number ofprocesses well known in the computer art such as scanning.

Printing a selected image on the decorative image layer may beaccomplished by engraving one or more cylinders, and using suchcylinders to print the selected engraved image on the decorative imagelayer with appropriate ink, according to processes well known in theprinting art. The resolution of the printing method should be in therange of about 30-59 dots per linear cm (75-150 dots per linear inch),i.e. about 872 cm.sup.2-3,488 cm.sup.2 (5,625-22,500 dots per squareinch). An illustrative example of how this printing process can be usedfor bottom printing a wood grain image on the bottom surface of thedecorative image layer comprises using a first cylinder for firstprinting a pattern of black or other dark colored ink corresponding tothe most prominent and most widely spaced grain lines, i.e. coarsegrain. A second cylinder may then be used for printing smaller, moreclosely spaced grain lines, i.e. fine grain, using black or other darkcolored ink.

A third cylinder may be used for printing colored bands on thedecorative image layer. For example, bands about 3.8 cm (1.5 inch) wideand spaced apart by about 3.8 cm (1.5 inch) are printed in a selectedbrown color. These bands give the effect of color variations within thewood, and the widths, spacing, and color of such bands are allselectable. A fourth cylinder may be used for printing a relativelysolid background color of a selected shade of brown or other colorcorresponding to the color of the type of wood being simulated. Also,additional cylinders may be used to provide even more image effects inthe printed or colored decorative image layer. It is considered that aperson of ordinary skill in the art could select more or fewer cylindersand printing steps to prepare a selected image.

These steps would be reversed for top printing an image on the topsurface of the printed or colored decorative image layer, i.e. the solidcolor would be printed first followed in succession by printing of thebands, fine grain, and coarse grain. Typically, there is some stretchingof the decorative image layer during printing. Therefore, the secondcylinder should be slightly larger than the first cylinder, the thirdslightly larger than the second, and the fourth slightly larger than thethird, so that the image printed with each cylinder is in properregister.

The ink used in the printing is preferably a solvent-based ink with nowax which is critical to producing a durable decorative laminatestructure that is resistant to delamination. During bonding together ofthe sheets and decorative image layers of the decorative laminatestructure, the layers of ink should bond with any adjacent decorativeimage layers as well as to the polymer used to prepare the printed orcolored decorative image layer and second sheet (for bottom printing) orfirst sheet (for top printing). A particularly preferred solvent-basedink comprises about 20-70% of a solvent, about 5-50% of a pigment, avinyl acetate polymer and formulation aids, and is available fromAmerican Mirrex.

The decorative image layer may also be colored throughout its thicknessby inclusion of pigments or colorants therein during its manufacture andthis colored image may be used as is without printing thereon, or thecolored image may be used as background for further printing of imagesthereon which may be seen through the first sheet of the structure.

In yet another embodiment, the decorative image layer comprisesvegetation, such as wood chips, grasses, thatch, flowers, for examplerose petals, wheat, grains, natural papers and others, such that thenatural color of vegetation is preserved. More than one decorative imagelayer comprising vegetation may be used in the decorative laminatestructure of the present invention. The use of multiple decorative imagelayers can provide a 3-dimensional or “floating” appearance to thedecorative vegetation in the decorative image layers. Each of thedecorative image layers is joined to a first sheet on one of itssurfaces such that the vegetation can be seen through the first sheetwithout significant distortion.

In further embodiment, the decorative image layer comprises crushedglass, which may be of various colors, such as black, gray, green, blue,orange, etc. More than one decorative image layer comprising crushedglass may be used in the decorative laminate structure of the presentinvention. The use of multiple decorative image layers can provide a3-dimensional or “floating” appearance to the decorative crushed glassin the decorative image layers.

The second sheet comprising polycarbonate may be either transparent oropaque. Hence, the second sheet may be comprised of a high percentage ofrecycled resin material, which do not necessarily retain transparency oreven contain materials that further enhance or modify the properties ofthe finished decorative laminate structure. However, the first sheet andthe second sheet are preferably thermally compatible. As used herein,“thermal compatible” means that when sheet layers of the decorativelaminate structure are bonded together under conditions of elevatedtemperature and pressure, the sheets undergo approximately equal thermalexpansion or contraction such that the surface of the decorativelaminate structure is substantially planar and interfacial stresses areminimized when the product is thermoformed.

The second sheet should exhibit good impact resistance, strength, andcompatibility with the decorative image layer. The thickness of thesecond sheet is between 0.13 and 12.7 mm (0.005-0.5 inch), preferablybetween 0.74 and 10 mm (0.03-0.5 inch), more preferably in the rangebetween 1.48 and 6.35 mm (0.063-0.126 inch), and most preferably in therange between 2.22 to 6.35 mm. The thickness is limited only byfunctionality.

The decorative laminate structure preferably further comprises aprotective layer, which is a transparent, hard, scratch-resistant orabrasion resistant coating or layer laminated to the top surface of thefirst sheet. These coatings or layers also increase the chemicalresistance of the decorative laminate structure and provide ananti-graffiti surface. For example, polycarbonate is not as hard orscratch resistant as may be desirable for certain applications. Thus,for an application where the exterior surface might be subjected tobeing scratched, it may be advantageous to provide a protective layerover the exterior surface. The protective layer may be a bilayer filmcomprising a protective layer on top of a sheet layer. The protectivelayer is preferably selected from the UV-cured or electron-beam-curedcrosslinked acrylic, vacuum-cured or UV-cured urethane, UV-cured orelectron-beam-cured silicon with acrylic or heat cured urethane orplastisol. A layer of polyurethane may be applied over the exteriorsurface to provide abrasion resistance. Alternatively, a biaxiallyoriented polyethylene terephthalate, such as MYLAR.RTM., or teflon, suchas TEDLAR.RTM., both available from DuPont Chemical Company, may belaminated to the top surface of the first sheet as a protective layer.More preferably, the protective layer comprises a UV-cured orelectron-beam-cured silicon to achieve glass appearance.

In one embodiment, a method of making a decorative laminate structurepreferably includes providing a first sheet and a second sheet, bothcomprising polycarbonate, providing at least one a decorative imagelayer between the first and second sheet, and heating and pressing thefirst and second sheet with the decorative image layer there-between fora time, temperature and pressure sufficient to cause the sheet layers ofthe decorative laminate structure to become tacky and bond to eachother. However, temperatures which cause decomposition, distortion, orother undesirable effects in the finished decorative laminate structureor sheet material should be avoided. Preferably, pressing of the firstand second sheet with the decorative image layer there-between occursbefore the application of heat.

In the laminating method according to this invention, a plywoodlaminating press, such as one from Onsrud Berthelsen, which has beenmodified to increase efficiency of platens heat transfer and to maximizethe number of channels, is preferably used. The increased number ofchannels allows to evenly distribute the temperature over the entiredecorative laminate structure. Also, the laminating press used in theprocess of making the decorative laminate structure of the presentinvention has electronic controls and feedback mechanisms to allow for aprecise control of the temperature and pressure of the press.

Furthermore, in the laminating press, a metal plate which is preferablya steel or aluminum plate having a thickness of 2 mm, a pressure pad tohelp equalize pressure which is preferably a compressible fabric pad,and a further flexible metal plate which is preferably a flexiblealuminum plate of 1.5-4 mm, are respectively aligned in parallelpressing relation, upon the exterior surface of the first sheet, orprotective layer if present. The fabric pad is preferably prepared fromcopper, silicone, NOMEX.RTM., which is an aramid fiber or fabricavailable from DuPont de Nemours, E. I. & Company, or a combination ofcopper and/or silicone and/or NOMEX.RTM.

More preferably, cast paper or embossing paper is disposed between themetal plate and exterior surface of the first sheet or protective layerto provide a texture to the laminate structure and/or to prevent thefirst polycarbonate sheet or protective layer from sticking to the metalplate. Examples of cast paper or embossing paper include patent paper(which provides high gloss), patina (which provides a satin finish),matte, stucco, ostrich, reptilian, glitter, topaz, grid, and allegro(which provides a leather appearance). A particularly preferred castpaper is available as ULTRACAST.RTM. from Sappi. In some instances, aprotective coat is not necessary because a heavily textured surface maynot display scratch marks.

In one embodiment, sufficient heat and pressure may be provided toeffect a bond between the sheet layers of the laminate structure in theabsence of a press, employing instead the weight of the superposed sheetlayers in conjunction with application of heat. To augment the reductionin pressure, a vacuum may be applied in order to remove trapped airbetween the adjacent sheet layers and the decorative image layers of thedecorative laminate structure. During the bonding process, if necessary,the polycarbonate materials may be bonded or fused together without theuse of adhesive.

Preferably, the laminating method comprises hot press bonding and coldpress bonding. Hot press bonding methods include, but are not limitedto, hot steam, electric heat, hot oil heated and other methods know inthe art. Cold press bonding methods include, but are not limited to,cold water, glycol cooled method, and other cooling methods well knownin the art. Hot press bonding is conducted at a temperature of about193.degree. C. to about 249.degree. C. (about 380.degree. F. to about480.degree. F.), preferably in the range of about 210.degree. C. toabout 227.degree. C. (about 410.degree. F. to about 440.degree. F.). Thepressures utilized in the bonding or laminating method are about 138 to2069 kPa (about 20 to about 300 pounds per square inch, psi), andpreferably are in the range of about 448 and 662 kPa (65 to about 96psi). The decorative laminate is held at the appropriate maximumtemperature and pressure for a period of time of about 0.1 to about 20minutes, preferably a period of time of about 0.1 to 5 minutes, mostpreferably for a period of time of about 0.17 minute (about 10 seconds).The optimal temperature for bonding may vary depending on the thicknessof the sheet materials used, and may be determined by those of ordinaryskill in the art. A temperature exceeding 249.degree. C. (480.degree.F.) and a pressure exceeding 2070 kPa (300 psi) is undesirable in hotpress bonding since the sheet layers may squeeze out of the aligneddecorative laminate structure.

This operation can be performed either with or without a vacuum press.Generally, the occurrence of bubbles in the final thermoplastic articleproduced is less likely to occur if the air is evacuated prior toapplying heat and pressure. The pressure on the decorative laminatestructure is increased to between 138 to 2069 kPa (about 20 to about 300psi), preferably to between 448 to 662 kPa (65 to 96 psi), with apressure of 634 kPa (92 psi) being most preferred. As a result ofpressure and heat, the sheets of polycarbonate are fused together andthe decorative image layer is embedded or encapsulated within thepolycarbonate sheets.

Following the hot press bonding, the bonded structure is allowed to coolby being held rigid at a temperature of about 10 to about 149.degree. C.(50.degree. F. to about 300.degree. F.), preferably 21.1 to 32.2.degree.C. (70.degree. F. to 90.degree. F.) and a pressure of about 7 to 2069kPa (about 1 to about 300 psi), preferably pressures of about 448 to 662kPa (65 to about 96 psi), more preferably pressures of about 552 to 662kPa (80 to 96 psi), most preferably about 634 kPa (92 psi) until itcools below the glass transition temperature of the sheet material.

Lamination may be conducted using individual relatively short sheets ofoverlaid material or using elongated sheets for later width wiseseparation. The material is preferably laminated in a stationary press,however, the material may be laminated using continuous castingequipment of the type used in the plastics industry for producinglaminate web material such as a machine employing upper and lowercontinuous belts. At least one of the belts is generally heated and thedecorative laminate structure is fed into the space between the beltsfor movement with the belts while being heated and pressed.

Once the decorative laminate structure is cooled below the glasstransition temperature of the polycarbonate, it may be shaped and formedinto a variety of useful articles by thermoforming or other knownmethods such as extrusion or injection molding. For example, thethermoplastic article can be thermoformed or otherwise shaped intoprivacy partitions, shower surrounds, table tops, or other uses. Thethermoplastic articles of this invention can be formed and moldedwithout substantially distorting the decorative image layer containedtherein.

In addition to illustrative articles which include counter tops, tabletops, cabinet doors, game boards, juvenile products, toys, panels forshower stalls, hot tubs, markerboards, indoor and outdoor signs,seamless vanity tops including sink, soap dish, and back splash, thedecorative laminate structure can be used in automotive, for example asa dashboard, marine, lighting, and aerospace products. For furtherexample, parts of a commercial aircraft interior can be readily formedfrom the decorative laminate sheets and include door linings and windowbezels, door handle escutcheons, emergency route indicator strips,instrument panels, etc.

While the invention has been described with particular reference tocertain embodiments thereof, it will be understood that changes andmodifications may be made which are within the skill of the art. Thepresent invention is limited only by the claims that follow.

EXAMPLES

The following examples are presented to illustrate the invention andshould not be construed to limit the scope of the invention.

Example 1 Production of ⅛″ Normally Thick Product Encapsulating aTextile

To obtain the desired laminate including uniform aqua colored textilewith patina finish on both sides and flat texture, the laminatingprocess was performed as follows. First the hot press platen waspreheated to a temperature of 475.degree. F. The cold press platentemperature was set at 65.degree. F.

Next the materials were assembled from top to bottom as follows: steelpress plate, Nomex pad (Nomex pressure distribution pads), aluminumseparation plate, release paper (patina finish Ultra-cast releasepaper), 0.060″ polycarbonate sheet (qty=2), textile (sheer nylontextile), 0.060″ polycarbonate sheet, release paper, aluminum separationplate, Nomex pad, and steel press plate.

After the assembly was completed, a thermocouple was inserted in-betweenthe first sheet of polycarbonate and the textile. Next, the assembly wasinserted in the hot press, the press was closed and the pressure wasincreased to 94 psi. The temperature was closely monitored until thethermocouple read 420.degree. F. Once the temperature reached thedesired 420.degree. F., the pressure was released and the press opened.Following hot pressing, the assembly was transferred to the cold pressset to cold press platen temperature of 65.degree. F. Next, the pressurein the cold press was increased to 94 psi. This transfer andre-pressurizing was completed in less than 3 minutes. The temperaturewas closely monitored until the thermocouple read 90.degree. F. Once thedesired temperature was reached, the decorative laminate structure wasremoved from the press.

As a result, the finished product was thermally fused through the fabriclayer, resulting in a monolithic structure. Surface finishes on the topand bottom of the product were uniform and even and the color of thefabric was uniform and even due to full saturation by the polycarbonateresin.

Example 2 Production of ¼″ Nominally Thick Product That is HeavilyTextured

To obtain the desired laminate including slightly foggy image layer withpatina finish on the back and heavy texture (Quo Mezzo, 3/16″ deep,v-shaped profile, sinusoidal pattern) on the front, the laminatingprocess was performed as follows. First the hot press platen waspreheated to a temperature of 475.degree. F. The cold press platentemperature was set at 65.degree. F.

Next the materials were assembled from top to bottom as follows: steelpress plate, Nomex pad (Nomex pressure distribution pads), aluminumseparation plate, release paper (patina finish Ultra-cast releasepaper), hard coated polycarbonate film (0.005″ thick film), orientedwith hard-coat against layer, 0.118″ polycarbonate sheet (qty=2),textile (clear Glassheen textile), 0.118″ polycarbonate sheet, releasepaper, aluminum separation plate, Nomex pad, and steel press plate.

After the assembly was completed, a thermocouple was inserted in-betweenthe first sheet of polycarbonate and the textile. Next, the assembly wasinserted in the hot press, the press was closed and the pressure wasincreased to 94 psi. The temperature was closely monitored until thethermocouple read 440.degree. F. Once the temperature reached440.degree. F., the pressure was released and the press opened. Next,the assembly was removed and split between the first release paper andhard-coated polycarbonate film. The Quo Quo Mezzo mold was placed facedown against hard-coated polycarbonate sheet. Next, the assembly wastransferred to the cold press set to cold press platen temperature of65.degree. F. and the pressure in the cold press was increased to 94psi. This transfer and re-pressurizing was completed in less than 3minutes. The temperature was closely monitored until the thermocoupleread 90.degree. F. Once the desired temperature was reached, thedecorative laminate structure was removed from the press.

As a result, the finished product was thermally fused through the fabriclayer, resulting in a monolithic structure. Surface finishes on thebottom of the product were uniform and even. The color of the fabric wasuniform and even due to full saturation by the polycarbonate resin andthe Quo Mezzo texture has been embossed in the polycarbonate structureuniformly.

Example 3 Production of ⅜″ Nominally Thick Product EncapsulatingBotanical Matter

To obtain the desired laminate structure, including botanical matterwith clear resin, flat texture, thatch reeds embedded on multiplelayers, and patina finish on both sides, the laminating process wasperformed as follows.

First the hot press platen was preheated to a temperature of 475.degree.F. The cold press platen temperature was set at 65.degree. F.

Next the materials were assembled from top to bottom as follows: steelpress plate, Nomex pad (Nomex pressure distribution pads), aluminumseparation plate, release paper (patina finish Ultra-cast releasepaper), 0.118″ polycarbonate sheet (qty=2), thatch (thatch reeds),0.236″ polycarbonate sheet, thatch, 0.118″ polycarbonate sheet, releasepaper, aluminum separation plate, Nomex pad, and steel press plate.

After the assembly was completed, a thermocouple was inserted in-betweenthe first thatch and 0.236″ polycarbonate sheet. Next, the assembly wasinserted in the hot press, the press was closed and the pressure wasincreased to 10 psi. The temperature was closely monitored until thethermocouple read 410.degree. F. Once the temperature reached440.degree. F., the pressure was increased to 30 psi. The temperaturewas closely monitored until the thermocouple read 420.degree. F. andonce it reached the desired temperature the pressure was again increasedto 94 psi. The temperature was closely monitored until the thermocoupleread 435.degree. F. Next, the pressure was released and the pressopened. The assembly was then transferred to the cold press set to coldpress platen temperature of 65.degree. F. and the pressure in the coldpress was increased to 94 psi. This transfer and re-pressurizing wascompleted in less than 3 minutes. The temperature was closely monitoreduntil the thermocouple read 90.degree. F. Once the desired temperaturewas reached, the decorative laminate structure was removed from thepress.

As a result, the finished product was thermally fused around and throughthe pieces of thatch, resulting in a monolithic structure. The surfacefinishes on the top and bottom of the product were uniform and even.

1. A method of making a decorative laminate structure comprising:providing a first sheet comprising polycarbonate, the first sheet havinga thickness between 0.13 and 12.7 mm; providing a second sheetcomprising polycarbonate, the second sheet having a thickness between0.13 and 12.7 mm; providing a decorative image layer between the firstand second sheet; and heating and pressing the first and second sheetwith the decorative image layer there-between at a maximum temperaturebetween 193 and 249.degree. C. and a maximum pressure between 138 and2069 kPa, wherein the time at maximum temperature and pressure isbetween 0.1 and 20 minutes.
 2. The method of claim 1, wherein heatingand pressing of the first and second sheet with the decorative imagelayer there-between occur at a maximum temperature between 210 and227.degree. C. and a maximum pressure between 448 and 662 kPa, whereinthe time at the maximum temperature and pressure is 0.1 to 5 minutes. 3.The method of claim 1, wherein heating and pressing of the first andsecond sheet with the decorative image layer there-between occur at amaximum temperature between 210 and 227.degree. C. and a maximumpressure of 634 kPa (92 psi), wherein the time at the maximumtemperature and pressure is about 0.17 minute.
 4. The method of claim 1,wherein the decorative image layer is selected from the group consistingof fabric, metallic wire, rod, bar, wood, stone, paper, and photographicimages.
 5. The method of claim 1, wherein the decorative image layercomprises vegetation.
 6. The method of claim 5, wherein vegetation isselected from the group consisting of wood chips, grasses, thatch,flowers, flower petals, wheat, grains, and natural papers.
 7. The methodof claim 1, wherein the decorative image layer comprises crushed glass.8. The method of claim 1, wherein the thickness of the first sheet isbetween 0.74 and 10 mm thick.
 9. The method of claim 1, wherein thethickness of the first sheet is between 1.48 and 6.35 mm thick.
 10. Themethod of claim 1, wherein the thickness of the first sheet is between2.22 and 6.35 mm thick.
 11. The method of claim 1, wherein the thicknessof the decorative image layer is between 0.0254 and 1.524 mm thick. 12.The method of claim 1, wherein the thickness of the decorative imagelayer is between 0.0254 and 0.05 mm thick.
 13. The method of claim 1,wherein the thickness of the decorative image layer is about 0.04 mm.14. The method of claim 1, wherein the thickness of the second layer isbetween 0.74 and 10 mm thick.
 15. The method of claim 1, wherein thethickness of the second layer is between 1.48 and 6.35 mm thick.
 16. Themethod of claim 1, wherein the thickness of the second sheet is between2.22 and 6.35 mm thick.
 17. The method of claim 1, further comprisingremoving air by vacuum prior to heating and pressing.
 18. The method ofclaim 1, further comprising cooling the first and second sheet with thedecorative image layer there-between at a temperature between 10 to149.degree. C. and pressure between 7 and 2069 kPa.
 19. The method ofclaim 18, wherein cooling the first and second sheet with the decorativeimage layer there-between is at a temperature between 21.1 to32.2.degree. C. and pressure between 448 and 662 kPa.
 20. The method ofclaim 19, wherein cooling the first and second sheet with the decorativelayer there-between is at pressure between 552 to 662 kPa.
 21. Themethod of claim 19, wherein cooling the first and second sheet with thedecorative layer there-between is at pressure of 634 kPa.
 22. The methodof claim 1, further comprising providing a protective layer, wherein theprotective layer is applied on at least one surface of the first sheet.23. The method of claim 22, wherein the protective layer is a bilayerfilm.
 24. The method of claim 22, wherein the protective layer isselected from the group consisting of UV-cured or electron-beam-curedcrosslinked acrylic, vacuum-cured or UV-cured urethane, UV-cured orelectron-beam-cured silicon with acrylic or heat cured urethane orplastisol, and combinations thereof.
 25. The method of claim 22, whereinthe protective layer is UV-cured or electron-beam-cured silicon.
 26. Themethod of claim 1, further comprising providing cast paper or embossingpaper.
 27. The method of claim 26, wherein cast paper or embossing paperis selected from the group consisting of patent paper, patina, matte,stucco, ostrich, reptilian, glitter, topaz, grid, and allegro.
 28. Themethod of claim 26, wherein the cast paper or embossing paper isdisposed between a metal plate and an exterior surface of the firstsheet or protective layer.